As shown in JP-A-10-291418, for example, a large number of the conventional lower sashes comprise a combination of a frame made of a plate metal and a glass run-channel made of rubber. However, the conventional lower sashes not only have relatively heavy weight itself but also cost high for being assembled and materials thereof. Therefore, these lower sashes have been gradually replaced by lower sashes made of resin, which can be manufactured by molding integrally. On the other hand, the lower sashes made of resin involve problems in that a descending window glass generates rattle sound with colliding against a glass guide and foreign substances such as sand or the like entered between the window glass and the glass guide generates noise. Therefore, in the lower sash made of resin, it becomes subject how to suppress or prevent from generating rattle sound or noise.
For example, JP-A-10-067228 discloses a window glass running stability device comprising a plate spring having means for removing dust on its sliding surface with the glass. The plate spring corresponds to a glass guide of the present invention and the window glass running stability device corresponds to a lower sash of the present invention. The means for removing dust concretely comprises irregularities provided on the sliding surface of the plate spring. The irregularities are any one of slits, projections, ribs, and crimp. According to the disclosure of JP-A-10-067228, the means for removing dust removes foreign substances itself causes generation of noise or the like.
JP-A-11-280331 discloses a window glass running stability device comprising a pair of glass holding sections having projecting pieces and provided contiguous to a frame corresponding to the base of the preset invention. The projecting piece corresponds to the glass guide of the present invention and is to be located at positions to slide on glass. Also, the glass holding section corresponds to the frame of the present invention. According to the disclosure of JP-A-11-280331, vibration of the glass holding section causing to generate noise is forcefully suppressed by enhancing the rigidity of the glass holding section provided as a base for the projecting piece.
JP-A-2000-240347 discloses a construction of an elevating door glass guide in which the glass guide formed in a tongue-like manner is connected to an inner surface of a side wall of a sash corresponding to the frame of the present invention. The glass guide comprises a projection having a sharp-pointed nose edge in sliding contact with a door glass surface. According to the disclosure of JP-A-2000-240347, the projecting portion and the door glass surface come into substantially linear contact with each other whereby influences of the glass guide on a window glass are decreased to make it hard to generate noise.
JP-A-2000-301946 discloses a lower sash structure for automobile door glass, in which guide pieces comprising a slide-holding surface made of a soft material different from that of a sash body are projectingly provided. According to the disclosure of JP-A-2000-301946, the slide-holding surface acts to suppress or prevent rattle sound (described as noise in JP-A-2000-301946).